The present invention relates to manifold assemblies of the type having an hydraulic fluid pressure inlet communicating with a plurality of valve chambers, each having an electrically operated valve ported therein for controlling, upon energization, fluid pressure selectively to individual outlets for the respective valving chambers. Manifolds of this type are employed for controlling pressure of hydraulic fluid in servo-actuators as, for example, clutch actuators in automatic speed-change power transmissions for motor vehicles where it is desired to control the speed change or shifting patterns of the transmission with an electronic controller. This arrangement has found widespread use in modern vehicle automatic transmissions because the electronic controller can receive in real time multiple inputs of vehicle operating parameters such as road speed, throttle position and engine RPM; and, the electronic controller can be programmed to provide optimum shifting patterns based upon known engine power available, vehicle mass and the operating parameter inputs.
However, in providing a shifting pattern for controlling hydraulic fluid pressure to each of the transmission speed change clutch actuators for effecting the desired shifting, it has been found that providing pressure sensors at the outlet of each of the electrically operated valves can provide a clutch actuator pressure signal in real time which is in actuality an analog of the force on the clutch which is in turn proportional to the torque transmitted by the clutch during engagement and disengagement. Such arrangement gives an electrical signal proportional to torque transmitted for a particular gear set and thus provides real time closed loop control of the transmission shifting. This arrangement has been found desirable as an alternative to predetermined shifting algorithms for open loop shift control by the electronic controller.
However, in providing the pressure sensors at each electric valve outlet for generating an electrical signal indicative of the shift clutch actuating pressure, it has been found disadvantageous from an assembly complexity, size and cost standpoint to provide individual electrical leads to the plurality of sensors and electrically operated valves on the manifold. Heretofore, individual wire leads with connector terminals have been connected to each pressure sensor and solenoid terminals on each valve and the leads bundled to form a wiring harness. This has been found to require a prohibitive large space for access to the terminals and the wiring harness within the transmission casing for the manifold assembly. Accordingly, it has been desired to find a way or means of electrically connecting to the plurality of pressure sensors and solenoid operated valves in a transmission shift control module or manifold assembly in a manner which is simple and easy to install in mass production and yet is sufficiently low in cost to render the technique desirable for competitive high volume light vehicle production.